was a real nail biter. At 4am, 10 hours into the firing, I realized that I had not gauged my propane reserves properly, when I looked at the tanks and realized that they were only about 1/5 full and covered with a thick layer of ice. I immediately put the water hose on them to melt the ice and keep them from freezing again, then I chewed my nails until 8:30 am when I could finally call the gas company for fresh tanks. They arrived just after 9am, and good thing to because I only had about 2 inches of fuel left in the tanks at that point.
The firing ran a total of about 18 hours, which is fairly normal for this type of firing, and most things came out ok, with a few exceptions:
….is without a doubt the Peter Pugger de-airing pugger/mixer. Until two years ago I did all of my clay and stone mixing in a large deep platter by hand, and it was killing my wrists. Hearing all the wonderful things Peter Pugger had to say on their website, I took the plunge and decided to spend the money and save my hands. I figured if the thing worked half as well as it was supposed to, I would be ok.
Well, it is now about 2 years since I got it and it does everything it is reputed to do, and does it very well. My wrists are now pain free, and I have saved hundreds of hours of time processing and blending clay bodies.
Blending wet clay bodies usually takes about 15 minutes of mixing, but mostly I mix dry materials with water (sometimes blending into wet bodies), and this takes a while longer, usually around 30 minutes.
In my work, keeping the character of the wild clay is of utmost importance, and I’ve found that de-airing generally kills that character dead. However, the de-airing is necessary in getting the water to penetrate the dry materials more quickly, so that I don’t have to let the pugged clay sit for a month before using.
My solution to this is to let the clay mix, then I de-air it once completely, followed by re-mixing the batch for 5 – 10 minutes after reintroducing air. This gives me clay that is not as easy to throw, but which gives very nice trimmed texture.
Here are some pictures of some clay from the other day which I collected from the mountain behind my home. I added the dry/damp clumps of clay to the hopper (removing as many large rocks as I could find), then water, then mixed. I repeated these three steps until the hopper was full, then mixed for about 20 minutes, turned on the vacuum pump, and de-aired completely.
Next I went to lunch. It was yummy. It was sunny on the deck and there was a cool breeze. The neighbors have a great cherry tree in full bloom and the wind was blowing the petals off, and they were fluttering across the yard like giant pink snowflakes. I noticed as I saw some of them fall across the deck that the wisteria was budding out and even starting to show some purple. Nice. I imagine the wisteria will be in full bloom a few weeks early this year.
After coming back to the studio, I re-introduced air to the mixing chamber and mixed some more, then pugged it all out and made some pots. The whole process took about 2 hours. It takes even less time if you decide not to include lunch, but I recommend including it.
Getting ready to set up a whole kiln load of glaze tests to fix my misbehaving ame (iron/ash) glaze, and realize that I’m out one very important ingredient, red ochre collected from a place right here in Taku. Completely forgot that I had used the last of it in my last glaze batch mixed up a couple months ago. Doh!
So…. Delay the mixing of test glazes for tiles and cups, I had to spend the day crushing and sieving red ochre. I haven’t used my man powered stamp mill in a while, and I added too much material to the mortar. My wooden pestle (4 foot long pole) that I use to stamp the material was just not up to the task because it was too light to sink down into the material and get it circulating in the mortar. To remedy this, I retrofitted one of my wooden pestles with some 3cm diameter round steel bar left over from a long piece of bar I cut into sections for my kiln’s grate bars.
This new pestle worked really great, so great in fact, that material was flying out of the mortar from the striking force. So I proceeded to cut down a large cardboard box to keep most of that stuff from flying out or away. It is really hard work digging it, carting it around, and crushing it, I hate to lose any at all.
So anyway, here are some pictures of today’s festivities, and I did wear a dust mask, so I don’t have to worry about getting red lungs…
Lately I’ve been working on ways to bring out the crackle in my teabowls, as well as make the crackle finer (without having to use them for decades or centuries, or reformulate my glazes, so in other words: cheat).
These two bowls had big crackle ( 1cm +-) and I reheated them, then doused in cold water.
***WARNING: Ceramics generally don’t like to be heated or cooled quickly. Don’t do this if you’re going to be upset about breaking a bowl!***
For the kohiki bowl, I heated and doused once to make the crackle smaller, then reheated to open the crackle wider, and closed the damper on my stove, to get that carbon to penetrate the crackle.
Because the body and the glaze were vitrified, but the white slip in between wasn’t, spots (where the slip was thickest) on the rim separated from the body and had to be restored with lacquer and gold (*1)
The results vary, and it is high risk, but you can get an idea about how your bowl may mature over years of use, and plus it’s just fun to play around with fire…
Another common way to bring out the crackle in you ware is to boil it in a pot of strong tea for a few minutes. The tannins will then turn brown, especially if you put the piece out in the sun to dry (or any other UV light). For an even darker, quicker reaction, after the piece is dry, apply some iron acetate. The iron acetate reacts with the tannins and turns quite black over a period of 24 to 48 hours. This is actually an old woodworking technique that I applied to pottery, and it works well, in addition to being non toxic.
***Results may vary***
(*1: I didn’t use real gold for this bowl, but I would on a very nice piece. For this piece I used a brass based metal powder. For more info on this kind of repair, check out Dave Pike’s blog, or store on Etsy)